Note some browsers will truncate these files if you click on the link to open it. Instead:

If using Firefox, right-click on verilog-mode.el and "Save Target As" verilog-mode.el.

If using Explorer, right-click on verilog-mode.el and "Save Link As." Choose to save the file, then when the save dialog shows up, change the filename from the wrongly defaulted "verilog-mode.el.htm" to "verilog-mode.el".

The source tree including tests is available at https://github.com/veripool/verilog-mode. If using this distribution you will need to "make" then install e/verilog-mode.el, not the verilog-mode.el in the top of the directory (which does not have the version number in it).

Note verilog-mode.el also comes as part of Emacs 21 and later. This version always lags the version here, by months to years. If you have issues with the version distributed with Emacs, please try the most recent release here.